“Geopolitical risks … kept investors on their toes. U.S. Secretary of State Pompeo demanded that Iran halt all uranium enrichment and give nuclear inspectors access to the entire country,” ANZ said in a note.

“However, investors are mindful of upcoming talks between Russia and Saudi Arabia about whether they should look at a controlled relaxation of over-compliance with their output cut agreement.”

OPEC may decide to raise oil output as soon as June due to worries over Iranian and Venezuelan supply and after Washington raised concerns the oil rally was going too far, OPEC and oil industry sources familiar with the discussions told Reuters.

The OPEC-led supply curbs have largely cleared an inventory surplus in industrialized countries based on the deal’s original goals, and stocks continue to decline.

Rising supply in the United States, where shale production is forecast to hit a record high in June, has limited the upward move in prices.